Crushing devices of the aforementioned type are used to reduce lump material for crushing, e.g. ores (iron ore, brown ore, copper ore, gold ore), rocks (granite, rock material, gypsum, serpentine, limestone), black coal, bituminous shale, marl, clay and overburden to a given desired particle size. Depending on the working conditions, the crusher units used in particular are hammer crushers, impact crushers, roll crushers, cone crushers, jaw crushers or rotary crushers.
The movability of the crushing devices required with respect to the face advance is assured in this case by the support structure being equipped with caterpillar crawlers, wheel travel gear or walking-type travel gear.
Semi-mobile crushing devices are configured such that they can be shifted in the desired manner by means of independent transport means, in particular by means of transport crawlers.
In the case of the appropriate crushing devices known hitherto, the crusher unit in many cases has a discharge conveyor means connected downstream of it, which consists of a discharge conveyor disposed below the crusher unit and a drawing conveyor cooperating with it, wherein the latter may also be constructed to be movable relative to the support structure.
The disadvantage of this known configuration is firstly that it has a relatively large mass as a consequence of the use of an additional drawing conveyor, wherein operation of the drawing conveyor requires the use of an appropriate drive means and is associated with an increased expenditure of energy. Secondly, the specifically highly stressed drawing conveyor—its accessibility rendered difficult as a result of its installation position between the crusher unit and the discharge conveyor—is particularly prone to wear and consequently requires repair or maintenance. The resulting relatively short service life of the drawing conveyor therefore has a detrimental effect on the feasibility of the entire crushing device.
Alternatively, appropriate crushing devices have also become known, wherein the discharge conveyor means only comprises a discharge conveyor that is not movable relative to the support structure. Consequently, the crushing device can only be adapted to changing working conditions by the crushing device itself being shifted as a unit, where necessary, and/or additional transport means being used, which cooperate with the relatively fixed discharge conveyor.